Tic-Tac-Toe is one of the first games that children master, so making it accessible and challenging again for adults is no small task. But that's just what Los Angeles-based puzzle games developer Hidden Variable Studios set out to do with Tic Tactics.

Based on a pen-and-paper modification of the original game, Tic Tactics enhances the strategic element of the Tic-Tac-Toe formula considerably, by placing players in a grid of nine 3x3 maps and requiring them to win over these smaller maps for ultimate possession of three down, three across or three diagonally. Additionally, players choose which 3x3 map their opponent must use after their turn, enhancing the competitive aspect of play.

The net result of these and other modifications to the formula is that stalemates become practically impossible, while winning takes considerably more diligence than that of the supercomputer in War Games. There are many winning moves, and based on Tic Tactics' 500,000 downloads in the last two months, 'not playing' is not among them.

"We tried to look at it within the great pantheon of games," Hidden Variable co-founder Charley Price tells Gamasutra. "We asked ourselves where this ranked up against the classics, say, go or checkers. Games which are mathematically solvable within a certain number of variations. We weren't happy with Tic Tactics until it was at least sophisticated enough to stump us."

Price and his co-founder David Marino both put strategy at the forefront of their design philosophy. Price has a background developing real-time strategy games, while Marino was at one point a ranked chess player, competing with the experts. The goal with Tic Tactics was to take the elegant simplicity of some of those classic games and distill it into an accessible free-to-play title with asynchronous play as well as local multiplayer. Plans are in the pipeline to introduce an AI opponent for single-player games.

"We wanted to create a visual and play style that was clean and simple," says Price. "We shied away from gimmicks, power-ups, things like that. The idea was to create a new classic."

Sitting at an average of 40,000 daily active users, the game is currently available on iOS and Android phones as well as through Amazon. A Facebook version is next on the docket.

"We want to be as ubiquitous as possible," Price explains. "The data we have suggests that Facebook is actually a great way to acquire additional users. [We look at it as] a gateway for mobile, for making these games as omnipresent in our players' lives as possible."